An observational study to evaluate the accuracy of a digital cough monitoring tool to reflect the incidence of COVID-19 and other respiratory infections at the community level in the city of Pamplona, Spain.

This is a single-center prospective observational study that pretends to evaluate the accuracy of an acoustic surveillance mobile app to detect individual episodes of cough among a monitored population, as well as the barriers and facilitators that might affect uptake of similar platforms at a population level.

The app in question, Hyfe cough tracker, runs in the background of smartphones, and records short snippets (<0.5 seconds) of explosive, putative cough sounds. These are then classified as cough or non-cough, using a convolutional neural network (CNN) model, and matched to GPS and time data collected by the smartphone.

The night-time cough of participants will be monitored for a 30-day period, and their clinical records will be reviewed regularly, specifically looking for diagnoses of cough-producing diseases, and with special emphasis on COVID-19.

Cough data will be used to create a heatmap of cough density and geographic distribution. Aggregated cough registries will be used to calculate the coughs per person-hour registered in the cohort. These data will be used to carry out an ARIMA analysis on three parallel time series at the community level: The incidence of respiratory disease in the monitored cohort, in the entire study area (including the Universidad de Navarra, and the neighbouring Cendea de Cizur), and the cough frequency per monitored hours.

Changes in cough frequency will also be compared to other environmental variables such as temperature and pollution level registered in the study area.

Inclusion Criteria:

• Be aged 13 or above,
• Own and regularly use a smartphone able to run the cough-tracking system,
• Be willing to install and regularly use it,
• Be current residents of Navarra, and
• Have an active relationship with the university (having interest in the study, or being a student or worker, be a patient with a cough-related diagnosis at the Clínica Universidad de Navarra, or Cizur's health centre).

Exclusion Criteria:

• Inability to accept the privacy policy and terms of use of the cough-tracking system.
• Inability to grant access to medical records.

Participants will be recruited in the Cendea de Cizur, a municipality composed by a cluster of villages south of the city of Pamplona, and the neighbouring town of Cizur Mayor, in the Comunidad Foral de Navarra (Spain), as well as in the different campuses of the University of Navarra. The 4,000 people living in the Cendea de Cizur are served by a public health center which receives 45,000 outpatients visits per year. Of these, approximately 12% are associated with respiratory diseases. The University of Navarra has over 11,000 registered students, 900 professors and over 600 other employees. Both the Cendea de Cizur and the University are served by the Clínica Universidad de Navarra, the largest private health center in the region, which provides medical care to an estimated population of over 100,000 people.